Single-phase and two-phase cooling with an array of rectangular jets

Experiments were performed to explore the effects of jet width, impingement velocity, and inlet subcooling on the cooling performance of an array of three confined rectangular FC-72 and ethanol jets impacting a 3.0 cm x 3.0 cm heated surface. The single-phase heat transfer coefficient increased with increasing jet velocity and/or jet width. A correlation for single-phase cooling was constructed by dividing the flow into impingement zones and confinement channel flow regions that are dominated by wall jet flow. Increases in jet velocity, jet width, and/or subcooling broadened the single-phase region preceding the commencement of boiling and enhanced critical heat flux (CHF). A new correlation was developed which fits the CHF data with good accuracy. Overall, better cooling performance was realized for a given flow rate by decreasing jet width. Pressure drop was for the most part quite modest, even for the smallest jet width and highest velocity tested. Overall, these results prove the present cooling scheme is highly effective at maintaining fairly isothermal surface conditions, with spatial variations of less than 1.2 and 2.6 degrees C for the single-phase and boiling regions, respectively. These results demonstrate the effectiveness of the present jet-impingement scheme for thermal management of next generation electronics devices and systems. (c) 2005 Elsevier Ltd. All rights reserved.